1. Field of the Invention
The present invention relates to a surround sound effect control device for selecting one of a plurality of surround sound effect circuits and, more particularly, to a surround sound effect control device for use in a television set.
2. Description of the Prior Art
Conventionally, a surround sound effect control device is provided in the audio device to allow the user to vary the reproduced sound effect according to his desire.
An example of a conventional surround effect control device is shown in FIGS. 4. Reference numeral 1 is a sound signal source selection circuit for selecting a signal source from a plurality of signal sources TV, V1, V2, and V3 by a source switch SW1 in response to the sound signal selection signal SA. The selected signal S is transmitted through a line L1. The sound sources are, for example, a television set TV, a first video cassette recorder V1, a second video cassette recorder V2, and a third video cassette recorder V3.
Reference numeral 8 is a surround effect pattern selection circuit for selecting one of a plurality of surround sound effect patterns by surround switches SW2 and SW3 switched to one of surround effect circuits 3, 4, 5, 6, and 7 in response to a surround effect selection signal SS. Surround effect circuits 3, 4, 5, 6, and 7 can modify the sound signal S from line L1 to various signal patterns of surround sound effect, such as "Dolby (Trade Mark) Surround", "Movie Surround", "Music Surround", "Monaural Surround", and "Surround-off". The modified sound signal S' is output through a line L2.
Each of surround sound effect circuits 3, 4, 5, 6 and 7 is briefly described as follows.
The dolby surround circuit 3 reproduces a sound from a sound signal including a delay between left and right sound signals.
The movie surround circuit 4 reproduces a sound by the delay of a difference signal between left and right sound signals.
The music surround circuit 5 reproduces a sound in a manner similar to that of the movie surround circuit 4, but the amount of the delay is reduced.
The monaural surround circuit 6 generates the difference signal from the original sound signal and a delayed signal thereof.
In operation, when the sound selection signal SA is input to the sound source selection circuit 1, the selection switch SW1 turns to connect one of the sound signal sources TV, V1, V2, and V3 to line L1. For example, it is assumed that the switch SW1 is turned such that the sound source V1 is connected to line L1, as depicted in FIG. 4 by the input signal SA.
When the surround effect selection signal SS is input to a surround effect pattern selection circuit 8, the surround switches SW2 and SW3 are turned to connect line L1 to one of surround effect pattern circuits 3, 4, 5, 6, and 7 and further to line L2. For example, it is assumed that the switches SW2 and SW3 are turned such that lines L1 and L2 are connected through the movie surround circuit 4 by the surround effect selection signal SS.
In this case, the sound signal S from the first video cassette recorder V1 is input to the movie surround circuit 4 in which the original sound signal S is modified to signal S'. The modified signal S', thus obtained, is further transmitted to a next stage through line L2.
However, according to the prior art surround sound effect control device, the selection of sound signal sources TV, V1, V2, and V3 and the selection of surround effect pattern circuits 3, 4, 5, 6, and 7 are performed individually, without any mutual relationship. Thus, it is necessary for the user to make two selections, one for the sound signal source and the other for surround sound effect pattern, every time when the viewing source is changed. For example, while watching a TV program which is usually served in a monaural sound, if a user switches to a video cassette recorder, associated with the sound signal source V1, it is necessary to further turn the switches SW2 and SW3 from the "Monaural Surround" to a position other than the "Monaural Surround" so that the stereo sound as usually served by the video cassette tape can be appreciated with its full performance.